/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2006, by Barak Naveh and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* ---------------------
 * DirectedSubgraph.java
 * ---------------------
 * (C) Copyright 2003-2006, by Barak Naveh and Contributors.
 *
 * Original Author:  Barak Naveh
 * Contributor(s):   Christian Hammer
 *
 * $Id: DirectedSubgraph.java,v 1.2 2007/05/22 15:52:54 kjellw Exp $
 *
 * Changes
 * -------
 * 05-Aug-2003 : Initial revision (BN);
 * 11-Mar-2004 : Made generic (CH);
 * 28-May-2006 : Moved connectivity info from edge to graph (JVS);
 *
 */
package org.jgrapht.graph;

import java.util.*;

import org.jgrapht.*;
import org.jgrapht.util.*;

/**
 * A directed graph that is a subgraph on other graph.
 * 
 * @see Subgraph
 */
public class DirectedSubgraph<V, E> extends Subgraph<V, E, DirectedGraph<V, E>>
		implements DirectedGraph<V, E> {
	// ~ Static fields/initializers
	// ---------------------------------------------

	private static final long serialVersionUID = 3616445700507054133L;

	// ~ Constructors
	// -----------------------------------------------------------

	/**
	 * Creates a new directed subgraph.
	 * 
	 * @param base
	 *            the base (backing) graph on which the subgraph will be based.
	 * @param vertexSubset
	 *            vertices to include in the subgraph. If <code>
	 * null</code>
	 *            then all vertices are included.
	 * @param edgeSubset
	 *            edges to in include in the subgraph. If <code>
	 * null</code>
	 *            then all the edges whose vertices found in the graph are
	 *            included.
	 */
	public DirectedSubgraph(DirectedGraph<V, E> base, Set<V> vertexSubset,
			Set<E> edgeSubset) {
		super(base, vertexSubset, edgeSubset);
	}

	// ~ Methods
	// ----------------------------------------------------------------

	/**
	 * @see DirectedGraph#inDegreeOf(Object)
	 */
	public int inDegreeOf(V vertex) {
		assertVertexExist(vertex);

		int degree = 0;

		for (E e : ((DirectedGraph<V, E>) getBase()).incomingEdgesOf(vertex)) {
			if (containsEdge(e)) {
				degree++;
			}
		}

		return degree;
	}

	/**
	 * @see DirectedGraph#incomingEdgesOf(Object)
	 */
	public Set<E> incomingEdgesOf(V vertex) {
		assertVertexExist(vertex);

		Set<E> edges = new ArrayUnenforcedSet<E>();
		Set<E> baseEdges = ((DirectedGraph<V, E>) getBase())
				.incomingEdgesOf(vertex);

		for (E e : baseEdges) {
			if (containsEdge(e)) {
				edges.add(e);
			}
		}

		return edges;
	}

	/**
	 * @see DirectedGraph#outDegreeOf(Object)
	 */
	public int outDegreeOf(V vertex) {
		assertVertexExist(vertex);

		int degree = 0;

		for (E e : ((DirectedGraph<V, E>) getBase()).outgoingEdgesOf(vertex)) {
			if (containsEdge(e)) {
				degree++;
			}
		}

		return degree;
	}

	/**
	 * @see DirectedGraph#outgoingEdgesOf(Object)
	 */
	public Set<E> outgoingEdgesOf(V vertex) {
		assertVertexExist(vertex);

		Set<E> edges = new ArrayUnenforcedSet<E>();
		Set<? extends E> baseEdges = ((DirectedGraph<V, E>) getBase())
				.outgoingEdgesOf(vertex);

		for (E e : baseEdges) {
			if (containsEdge(e)) {
				edges.add(e);
			}
		}

		return edges;
	}
}

// End DirectedSubgraph.java
